The present invention relates to rotary electrical couplings and in particular rotary inductive couplings for transmitting a low level electrical signal and/or an electrical power signal across a rotating junction.
Rotary couplings are useful where it is desired to conduct electrical signals from a stationary to a rotating member or as between two relatively rotating members.
In motor vehicles it has been the practice to provide slip rings, rotary wiper contacts or a ribbon of parallel electrical conductors with the ribbon spirally wound in the form of a "clock spring" for electrically connecting accessory switches and the vehicle horn button in addition to supplying the energy to the steering wheel mounted airbag inflator for effecting inflation in a steering column/steering wheel air bag installation. However, slip rings, wipers and clock spring conductors have proven to be noisy, costly and extremely difficult to assemble for high volume mass production of vehicles. Therefore, it has been desired to provide a relatively frictionless, simpler and lower cost alternative for connecting electrical controls and devices mounted on the steering wheel to the vehicle wiring harness.